An increasing demand for higher performance computers has driven a greater effort to increase the performance of internal device components. The performance of a computer's CPU is highly dependent upon the bandwidth and capacity of memory devices that are accessible to the CPU. The bandwidth and capacity limitations of such memory consequently limit the performance of the CPU. Thus, industry leaders are motivated to increase the accessibility of memory devices to a CPU.
According to one approach, memory devices may be attached directly to the CPU package substrate rather than on the motherboard. Although a variety of memory devices can be integrated on the CPU package substrate, the memory devices cannot be reconfigured after package assembly.
The package assembly process includes attaching a CPU and memory devices onto a CPU package substrate. Conventional methods integrate memory devices on the CPU package substrate by soldering them directly on the CPU package substrate during the package assembly process. A conventional CPU package substrate 100 is illustrated in FIG. 1A. As shown in FIG. 1A, a processing device interface 102, such as a land grid array (LGA), is disposed on a CPU package substrate 104. Additionally, memory device electrical interfaces 106 may be disposed on the CPU package substrate 104 beside the processing device interface 102. Memory device electrical interfaces 106 may also be LGAs.
FIG. 1B illustrates a conventional CPU package 101 after completion of the CPU package assembly process. The conventional CPU package 101 includes a processing device 108 and memory devices 110 mounted on the CPU package substrate 104. In embodiments, the processing device 108 and memory devices 110 mount directly on the package substrate 104. For instance, the processing device 108 and memory devices 110 may be flip-chip bonded on the CPU package substrate 104 via an array of solder joints (not shown). Soldered connections are permanent connections that, once reflowed and cooled, cannot be removed without subjecting the entire CPU package 101 to a reflow process. Thus, the memory devices 110 are permanently attached to the CPU package substrate 104 and cannot be easily removed. Once the memory devices 110 are attached and a customer purchases the assembled package, the customer cannot reconfigure the particular arrangement of memory devices 110. The assembled package is thus a highly specific device that is useful in only a few applications.
As technology continues to develop, the marketplace becomes more segmented with varying requirements of memory capacity and bandwidth needs. Additionally, customers increasingly look for custom memory arrangements for their specific applications. Due to the inability to reconfigure the memory device arrangement after CPU package assembly, current producers of these CPU package assemblies are having to generate numerous model variations to keep up with customer preferences. Having numerous model variations can be cumbersome, time consuming, and expensive to maintain.